a) Field of the Invention
The present invention relates to a lighting apparatus, particularly to a mounting structure of a shade for use with an electric table lamp.
b) Prior Art
Conventional lighting apparatus, particularly a conventional electric table lamp, is disclosed for example in Japanese Utility Model Un-Examined Publication No.6-50130 and Japanese Utility Model Examined Publication No.7-51691. The Publication No. 6-50130 discloses an electric lamp which comprises: a shade; an arm; and a lamp mounted to the shade, said shade having one end rotatably mounted to an upper end of said arm through a rotating mechanism. In this prior art, a socket and the lamp are attached to the shade, thus enabling the adjustment of the lighting direction by the rotation of the shade. The latter prior art or the Publication No. 7-51691 discloses another table lamp which comprises: an arm; an attachment plate mounted to the arm; a straight-tube-type lamp; and a socket provided on the attachment plate for retaining the lamp; and a cylindrical shade surrounding both the attachment plate and the lamp, wherein a fastening cover is mounted to said attachment plate, so that the shade can be locked in a manner capable of rotating around an axis of the lamp. In this prior art, the shade is independent of the socket and the lamp, so that the adjustment of the direction of light can be realized by rotating the shade only.
According to the structure disclosed by the former prior art, however, as the lighting tool which is rotatable relative to the arm consisted of the shade, the socket and the lamp, the tool was so heavy that it required other mechanisms such as a tightening mechanism or a stopper mechanism for tightening or making the rotating mechanism stationary, and thus, the structure became too complicated. Besides, to move the shade which was once made stationary, it was necessary to relax the tightening mechanism or to release the stopper mechanism, thereby resulting in a nuisance in handling the apparatus. Furthermore, as the socket and the lamp were mounted to the shade, there was resulted a certain constraint in designing the shade. According to the structure of the latter prior art, whilst the weight of the movable part became smaller, it was necessary to attach the shade, using the fastening cover which is separate from the shade, so that not only the attaching and detaching works of the shade were a nuisance, but also the increased costs were resulted.
To eliminate the above problems, it is a main object of the invention to provide a lighting apparatus which realizes an easier attachment and detachment as well as an easier rotation of the shade with a simple and less expensive structure.
It is another object of the invention to provide a lighting apparatus with an enhanced degree of freedom in designing the same.
To attain the above objects, there is provided from a first aspect of the invention, a lighting apparatus which comprises: a head having a socket; an electric light bulb mounted to the socket of the head; and a shade for covering the electric light bulb, wherein one of the head and the shade is formed with a protrusion, while the other thereof is formed with a groove which is opposite to the protrusion, whereby the shade is mounted to the head by allowing the protrusion to engage with the opposite groove.
According to the first aspect of the invention, the shade can be easily mounted to the head through the engagement of the former to the latter by fitting the protrusions formed on the shade or the head into the grooves formed on the head or the shade.
Further, there is provided from a second aspect of the invention, a lighting apparatus with the structure of the first aspect, wherein one of the groove and the protrusion is formed around an axis of said head so that at least a part thereof may construct an arc-shaped portion such that the protrusion or the groove opposite thereto may be slidable relative to the arc-shaped portion, whereby said shade is mounted to the head in a manner capable of rotating around the axis of said head.
According to the second aspect of the invention, when a user rotates the shade around the axis of the head, the protrusions or grooves formed on the shade are slidable within the arc-shaped portions along the grooves or protrusions formed on the head, so that the shade is easily rotated around the axis, thereby easily adjusting the direction of light.
In addition, according to a third aspect of the invention, there is provided a lighting apparatus with the structure of foregoing aspects, wherein said head and shade are each formed with at least one pair of the protrusions or the grooves. Thus, the shade can be fixedly mounted to the head without wobbling.